Finding the Fourth Proportional to 1,428.20, 1,970.34 and 838.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.20 : 1,970.34 = 838.52 : x
2. Step 2: Convert to fraction form
   1,428.20/1,970.34 = 838.52/x
3. Step 3: Cross multiply
   1,428.20x = 1,970.34 × 838.52
4. Step 4: Simplify right side
   1,428.20x = 1,652,169.50
5. Step 5: Solve for x
   x = 1,652,169.50/1,428.20
6. Step 6: Final answer
   x = 1,156.82